Wal-Mart retakes the No. 1 slot on the Fortune 500 this year. See where America's largest corporations rank, and why.

The retail giant reclaims the top spot on the Fortune 500, making it the largest company in the United States for the fifth time in six years. The company suffered a series of
public relations gaffes last year, but has launched a crusade to spruce up its image. It now employs 1.9 million people worldwide and revenues are up 11% over last year, but
profits grew less than 1%, amid a slowdown in same-store sales.